Tire condition detection system and induction feed method thereof

• US 20070222570A1
• Filed: 02/20/2007
• Published: 09/27/2007
• Est. Priority Date: 02/28/2006
• Status: Active Grant

• Current Assignee: OKI Electric Industry Company Limited
• Original Assignee: OKI Electric Industry Company Limited
• Inventors: Ishii, Eiichi, Nagata, Shiro, Ou, Hok
• Granted Patent: US 8,044,783 B2
• Time in Patent Office: Days
• US Class Current: 340/447
• CPC Class Codes: B60C 23/0408 transmitting the signals by non-mechanical means from the wheel or tyre to a vehicle body mounted receiver
• CPC Class Codes: B60C 23/0444 Antenna structures, control or arrangements thereof, e.g. for directional antennas, diversity antenna, antenna multiplexing or antennas integrated in fenders

Abstract

An external antenna positioned external to a tire, and an internal antenna provided inside a valve of the tire, which transmits and receives power by electromagnetic waves in a predetermined high frequency band is substituted as a new source of power, for a tire pressure/temperature detection device that conventionally uses a battery power source. If the electromagnetic waves in a predetermined high frequency band are well matched to the physical structure and electrical structure of the tire, then, in the space between the tire and a wheel, a magnetic field component is distributed that is substantially perpendicular to the plane that includes the maximum diameter of tire. If the internal antenna is matched to the direction of maximum magnetic field reception, when the tire rotates, and when the position of the wheel is stopped, substantially stable power may be received.

Claims

1. A tire condition detection system comprising:

a tire, internally provided with conductive reinforcement material;

an external antenna, fixed in proximity to the outside of said tire, and radiating to said tire electromagnetic waves that generate an induce alternating current in said reinforcement material;

an internal antenna, fixed at said tire side, receiving an alternating magnetic field generated in the space inside said tire due to said induced alternating current generated in said reinforcement material, and outputting a received signal;

a power source, fixed at said tire side, converting said received signal into alternating current power and outputting source power; and

a detector, fixed at said tire side, operated by said source power, detecting predetermined conditions inside said tire and transmitting the detected signal by electromagnetic waves to said external antenna via said internal antenna and said reinforcement material.

2. A tire condition detection system comprising:

a wheel, with a valve fixed thereto that has an air ingress and egress aperture;

a tire, internally provided with conductive reinforcement material and mounted on said wheel;

an external antenna, that is fixed in proximity to the outside of said tire, radiating electromagnetic waves that have an alternating magnetic field component that is substantially parallel to the axis of rotation of said tire, and that generates an induce alternating current in said reinforcement material due to said alternating magnetic field component;

an internal antenna, fixed at said valve, receiving said alternating magnetic field component supplied with power by said external antenna, and receiving a secondary alternating magnetic field generated by said reinforcement material in the space between said tire and said wheel due to said induced alternating current, and outputting a received signal;

a power source, fixed at said valve, converting said received signal into alternating current power and outputting source power; and

a detector, fixed at said valve, operated by said source power, detecting predetermined conditions inside said tire and transmitting the detected signal by electromagnetic waves to said external antenna via said internal antenna and said reinforcement material.

3. An induction supply method of a tire condition detection system comprising:

a tire, internally provided with conductive reinforcement material;

an external antenna, fixed in proximity to the outside of said tire, radiating to said tire electromagnetic waves for power use, and receiving electromagnetic waves for signal use;

an internal antenna, fixed at said tire side, receiving said electromagnetic waves for power use radiated from said external antenna via said reinforcement material, and transmitting said electromagnetic waves for signal use via said reinforcement material to said external antenna, the induction supply method comprising;

radiating from said external antenna electromagnetic waves with an alternating magnetic field component substantially parallel to the axis of rotation of said tire, generating an induced alternating current in said reinforcement material due to said alternating magnetic field, and generating a secondary alternating magnetic field in a space between said tire and a wheel due to said induced alternating current;

receiving with said internal antenna said alternating magnetic field that is power supplied by said external antenna and receiving with said internal antenna said secondary alternating magnetic field, and outputting a received signal;

converting said received signal into source power.

10. The induction supply method according to claim 3, wherein

said external antenna comprises a plurality of turns of conductive wire wound in a solenoid shape,

said external antenna is disposed either directly above the outer peripheral surface of said tire, or at an angle to that position, so that the central axis of said external antenna is substantially parallel to the axis of rotation of said tire,

said external antenna receives high frequency power from a high frequency power source and radiates an alternating magnetic field in the direction of the central axis of the solenoid shape such that said alternating magnetic field of both ends of said solenoid shape diverges, and widens out into the surrounding space and a portion of components of said magnetic field passes through a side face of said tire substantially perpendicularly.

11. The induction supply method according to claim 10, wherein said external antenna comprises a solenoid, wound with a plurality of turns, with an extended dimension in the lateral direction, curved in the lateral direction an arc shape around the outer peripheral surface of said tire.

12. The induction supply method according to claim 10, wherein said external antenna is formed of a solenoid shape using tape-shaped conductive foil.

13. The induction supply method according to claim 3, wherein

said external antenna is formed of a solenoid, and said solenoid is curved in the central axis direction such that the two ends of said solenoid approach the two side faces of said tire, and said solenoid is disposed with substantially left-right symmetry to said tire,

said external antenna receives high frequency power from a high frequency power source and radiates an alternating magnetic field in the direction of the central axis of the solenoid shape such that said alternating magnetic field of both ends of said solenoid shape diverges, and widens out into the surrounding space and a portion of the components of said magnetic field passes through a side face of said tire substantially perpendicularly.

14. The induction supply method according to claim 3, further comprising a bar shaped core, with a main component of soft iron or ferrite, and provided along the central axis of said external antenna.

15. The induction supply method according to claim 3, wherein said external antenna is formed of a solenoid, and a C-shaped core is provided with a main component of soft iron or ferrite along the central axis of said solenoid.

16. The induction supply method according to claim 3, wherein

said external antenna is formed in a loop shape with one turn of conductive wire, said external antenna having a central axis that is substantially the same as the rotational axis of said tire, and being disposed between said tires on the left and the right of a vehicle at a predetermined position from a side of said tire,

said external antenna receives high frequency power from a high frequency power source and an alternating magnetic field vortex is generated around said conductive wire of said external antenna, and a portion of components of said magnetic field vortex passes through a side face of said tire substantially perpendicularly.

17. The induction supply method according to claim 16, wherein

said loop shaped external antenna is formed with one turn in a loop shape or a ring shape, said external antenna having a central axis that is substantially the same as the rotational axis of said tire, disposed between said tires on the left and the right of a vehicle at a predetermined position from a side of said tire,

said external antenna receives high frequency power from a high frequency power source and an alternating magnetic field vortex is generated around said conductive wire of said external antenna, radiating an alternating magnetic field with substantially the same intensity at the circumference of a circle with the rotational axis of said tire as the center, and a portion of the components of said alternating magnetic field passes through a side face of said tire substantially perpendicularly.

18. The induction supply method according to claim 3, wherein said conductive reinforcement material comprises metal wire or metal mesh.

4. An induction supply method of a tire condition detection system comprising:

a tire, internally provided with conductive reinforcement material;

an external antenna, fixed in proximity to the outside of said tire, radiating to said tire electromagnetic waves for power use, and receiving electromagnetic waves for signal use;

an internal antenna, fixed at said tire side, receiving said electromagnetic waves for power use radiated from said external antenna via said reinforcement material, and transmitting said electromagnetic waves for signal use via said reinforcement material to said external antenna;

a detector, fixed at said tire side, operated by source power, detecting predetermined conditions inside said tire and transmitting the detected signal by electromagnetic waves to said external antenna via said internal antenna and said reinforcement material, the induction supply method comprising;

radiating from said external antenna electromagnetic waves with an alternating magnetic field component substantially parallel to the axis of rotation of said tire, generating an induced alternating current in said reinforcement material due to said alternating magnetic field, and generating a secondary alternating magnetic field in a space between said tire and a wheel due to said induced alternating current;

receiving with said internal antenna said alternating magnetic field that is power supplied by said external antenna and receiving with said internal antenna said secondary alternating magnetic field that is power supplied by said external antenna, and outputting a received signal;

converting said received signal into said source power and supplying said source power to said detector.

5. An induction supply method of a tire condition detection system comprising:

a wheel, with a valve fixed thereto that has an air ingress and egress aperture;

a tire, internally provided with conductive reinforcement material, and mounted on said wheel;

an external antenna, fixed in proximity to the outside of said tire, radiating to said tire electromagnetic waves for power use, and receiving electromagnetic waves for signal use;

an internal antenna, fixed at said valve, receiving said electromagnetic waves for power use radiated from said external antenna via said reinforcement material, and transmitting said electromagnetic waves for signal use via said reinforcement material to said external antenna;

a detector, fixed at said valve, operated by source power, detecting predetermined conditions inside said tire and transmitting the detected signal by electromagnetic waves to said external antenna via said internal antenna and said reinforcement material, the induction supply method comprising;

radiating from said external antenna electromagnetic waves with an alternating magnetic field component substantially parallel to the axis of rotation of said tire, generating an induced alternating current in said reinforcement material due to said alternating magnetic field, and generating a secondary alternating magnetic field in a space between said tire and said wheel due to said induced alternating current;

receiving with said internal antenna said alternating magnetic field that is power supplied by said external antenna and receiving with said internal antenna said secondary alternating magnetic field, and outputting a received signal;

converting said received signal into said source power and supplying said source power to said detector.

6. The induction supply method according to claim 5, wherein

said external antenna comprises a small circular antenna of a plurality of turns of conductive wire with an insulating coating wound in a solenoid shape, and said external antenna receives a high frequency power supply from a high frequency power source and radiates said alternating magnetic field component substantially parallel to the axis of rotation of said tire.

7. The induction supply method according to claim 6, wherein there are two of said external antenna, with said two external antennae positioned at substantially 90°

or more to each other on the circumference of a circle with the rotational axis of said tire at the center, and

said source power generated by said secondary alternating magnetic field of said two external antennae is supplied to said detector.

8. The induction supply method according to claim 7, wherein said two antennae are disposed at positions substantially on opposite sides to each other on the circumference of a circle with the rotational axis of said tire at the center.

9. The induction supply method according to claim 6, wherein there are two of said external antenna, with said two external antennae positioned in the same direction to the rotational axis of said tire and said two external antennae disposed one on each side of said tire such that they have the same central axes as each other, and the direction of flow of said alternating current in said external antennae is adjusted such that the direction of said alternating magnetic fields radiated by said respective external antennae are the same, and

said source power generated by said secondary alternating magnetic field of said two external antennae is supplied to said detector.